Rockwell-automation 1756-CFM ControlLogix Configurable Flowmeter Modul Manual de usuario descargar pdf (Pagina 143)

143Rockwell Automation Publication 1756-UM010B-EN-P - December 2011

Frequency Accuracy 143

Frequency Accuracy in

Totalizer Mode

There are two steps to calculating frequency accuracy in

totalizer mode.

1. Calculate frequency accuracy.

2. Determine the application’s operating conditions and add the error for

those conditions to the value obtained in step 1.

The following values must be added to your frequency accuracy results

in totalizer mode:

 Crystal error - 0.005% @ 25°C

 Drift and crystal error - 0.01% from 0° to 60°C

Calculate Frequency Accuracy

You can calculate frequency accuracy in totalizer mode for:

 Frequency Period

 Speed

 Frequency average

Frequency Period

For frequency period, you must know:

 User-defined sample time period (T

)

 Application frequency (F

)

 Number of accumulated counts in sample time (Counts)

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Rockwell-automation 1756-CFM ControlLogix Configurable Flowmeter Modul Manual de usuario Pagina 143